Thailand's Army is claiming success in the government's war on drugs and reports a sharp drop in the flow of illegal drugs across its borders. But, United Nations drug officials say an effective public awareness campaign is needed to sustain the gains.

The Thai Army says it has sharply reduced illegal drugs coming into Thailand, by tightening controls at the border. The announcement comes after one month into the war on drugs launched by Prime Minister Thaksin Shinawatra.

The army, with troops from the International Security Operations Command (ISOC), has carried out more than 600 special patrols and raids along border areas near Cambodia, Laos and Burma.

ISOC chief of staff General Veerachai Iamsa-ad says the number of methamphetamine tablets coming into the country has decreased dramatically. Officials say the army seized 430,000 methamphetamine tablets in February - just a fraction of the 60 million on average that used to come into Thailand from Burma every month.

"But the influx of methamphetamines to our country has decreased due to many reasons; first of all ... the intensity of the operation, and second, the demand inside the country has also decreased due to the police and the provinces operations that have increased," he said.

In the first month of the three-month campaign, the street price of methamphetamines, commonly known yaa baa, or crazy medicine, has increased up to 400 percent.

General Veerachai says the campaign will continue.

"After these three months have passed the operation… will continue and we will try our best not to let anyone bring in the methamphetamines or any other drugs into the country," he said. "Please be assured we will do that as long as there is any threat to the country."

The campaign has led to the deaths of more than 1,100 alleged drug dealers. Twenty thousand people have been arrested. Thousands of others, fearing for their lives, have surrendered to police.

Human rights organizations and the international community have raised alarms over the killing spree. The government and army blame most of the deaths on drug gang syndicates killing dealers.

But the United Nations Drug Control Program (UNDCP) regional representative, Dr. Sandro Calvani, says he welcomes the army's success. He added that an effective public awareness campaign, like those carried out in Japan, South Korea, Singapore and Hong Kong, would be crucial for long-term success.

"Whether [the campaign] will be effective or not [in Thailand] is too early to say now," he said. But "if some conditions are respected there's no reason to think why what has worked in Singapore and South Korea should not work in Thailand."

He says such campaigns should extend to the general public as well as schools where more than one million youths are believed to be addicted to methamphetamines.